1. Field of the Invention
This invention relates to a method of removing dispersed oil from oily water by contacting the oily water with sulfur to cause the oil to coalesce or agglomerate. It particularly concerns the method in which the water containing the dispersed oil is passed through a bed of granular solid phase yellow sulfur to coalesce the dispersed oil. It also concerns a system in which a slurry of yellow sulfur is mixed with the oily water to cause the oil to coagulate with the sulfur slurry.
2. Setting of the Invention
In recent years the Government and public have become increasingly aware of the need to eliminate pollution of our atmosphere and our water. Industry is moving to minimize these pollution problems both due to a sense of public obligations and to meet legal requirements. Although many of our larger industrial sites are experiencing air pollution problems, it is believed that as a nation the elimination of the pollution from our water systems is more urgent.
Many water pollution problems are recognized, but the solution is not always readily apparent. A particularly troublesome area is the pollution of water by floating and dispersed oil. This problem is nearly always present around oil refineries and oil producing facilities. Of course, there are known ways of removing essentially all oil from such oily water. However, such known means are either too expensive or not adaptable to such large scale operations. Some removal systems also produce large amounts of oily sludge that cannot be easily disposed of.
Many of the oil field waters contain up to about 100 to 500 ppm of water. This should be reduced to essentially zero ppm of oil if the water is to be dumped into our surface streams. If this water is to be injected into an underground reservoir to aid in driving out the oil, as is common in secondary recovery operations, the oil content should be less than about 10 ppm. An economical way of removing this dispersed oil from such water would be a big help in reducing this phase of water pollution. The invention described herein provides such a system.